Electric switch



J. D. HILLIARD ELECTRIC swITcn Filed Nov. 20. 1922 June Inlll/ltlllllllllllllllllllill,(Ill/1'lI/lIIll/llllllllllllIllllll,IIIIl[lill/111111111111111!![lll/IIIA?)l"'Wl His Atbofng.

' a consi erable body of cooling liquid be-4 Patented June 7, 1927.

UNITED STATES JOHN n. Hamann,

PATENT OFFICE.

F BCHENECT-AD`Y, NEW AYOIB'K, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, .A CORPORATION 0F NEW YORK.

Application led November 20, 1922. Serial No. 601,955.

My invention relates to electric switches of the type wherein contacts are separated beneath an arc extinguishing liquid, and more particularly to an improved arrange.- ment of the contacts of such switchesl whereby the circuit may be safely and effectively interrupted. l

In the operation of switches having their contacts immersed in a liquid, there is frequently produced in the switch tank high pressure due to the intense local heating and consequent dissociation and volatilization of the liquid by the arc between the contacts. This pressure may be so severe as to rupture the switch tank, and, in any case, there is grave danger of re and explosions if the highly heated vapors and gases have -easy access to the air.

It is, therefore, a principal object of my invention, tol provide an arrangement of switch contacts designed to keep the arc near the bottom of the tank where it is 'subjected to hydrostatic pressure which assists in extinguishing it, and from whence the hot ases and vapors must pass through fore they rise to the surface thereof.

Other objects and advantages will become apparent as my invention isA considered in. connection with the accompanying drawing, the single gure of which shows a tank ,10 provided with an insulating lining 11 adapted to contain lan insulating/or arc extinuishingiluid 12. l Annular expansion chamr casin'gs 13` are disposed around the inner sides of the insulating lining 11 and held in place by thev supports 14 which restA agalnst the insulating lining 11. A cover 15 for the tank 10 is rovided with avent -15 to ermit escape o gases from the tank and with apertures toV receive insulating bushings 16 for stationary ,electrodes 17 of the switch, the bushings being heldin place by clamping rings 18.' An aperture is also provide in the tank cover v15 .to allow the passage of an operatingrod 20 through the stuiiing box 21. 'An insulating primary contact `chamber casing 25 is suspended from the cover '15 by the bolts 26, theheads of which are covered by insulating nuts 27, proper alignment being maintained byethe spacers 28. The primary contact cham ris vented b the apertures-.29 in the top memberof t eccasing 25, and is so formed as to direct any gases vgenerated beneath it upwardly along its outer surface. Expansion chamber casings v32 are attached to the side members of the casing 25. The lower central portion of the casing is adapted to form an arc deiiecting bailie 33.

Primary contact brushes 35 are attached to the stationary electrodes 17 and engage,

in the closed position of the switch, with a casing 25. The lower ends of the secondary Contact levers 40 consists of cylindrical casings adapted to hold the movable secondary contacts 50l which are-designed to be actuated toward thecenter of the tank by the springs 51 which act upon shoulders 61 formed on the contacts. The nuts 52 limit the travel of the secondary contacts 50 in the direction toward the center of the tank. Goo-d secondary contacts v50 and the secondary contact levers 40` is maintained by the iiexible strips `53. y

.In operating thel switch' from closed position, the rod20`is moved downwardly to separate the brid ing member 36 from the primarycontact rushes 35, and to break the toggle connection between thesecondary contact levers 40 which are in an inclined position and tend to drop under the force A of their'- own weight vand by magnetic repulsion, thereby facilitating the opening operation of the switch. This arran ement of secondary contact levers has the urther advantage that it .helps to intensify the magnetic field of the switch in the. neighbor ood of the secondary contacts where the nal break in the circuit is made and thus increases the disrupting force which this iield exerts. upon any are formed between these contacts-upontheir separation. Further movement of the red 20 lwill cause the secondary contact members to separate, and, if the switch 1s loaded, an arc will be proelectrical connection betweeen the 50 prising duced between these contacts. The secondary contacts and their associated conduct ing leads are arranged so that the magnetic field of the switch acts to force the arc downwardly against itsnatural tendency to rise, thereby rupturing it near the bottom of the tank and insuring intimate contact between the cooling liquid and the resulting hot gases which ultimately escape to the at- O mosphere through the top of the tank.

The battle 33 forms apart of the bottom of the primary contact chamber, and is provided ier the purpose of protecting this chamber against the arc formed by breaking l5 the circuit.

The compression chambers 13 and 32 are lled with a compressible gas which effectively absorbs the excess pressure generated within the tank by the arc incident to separa tion of the secondary contacts under load. The location of the chambers 13 in proximity to the point atwhich the circuit is finally broken is of especial advantage in that it avoids the necessity of accelerating a large bo'dy of oil and this serves to prevent the igeneration of the excessive pressure which would otherwise be produced within the tank. 'Ihe chambers 32, which are interposed directly in the path which the gases generated within the tank must follow in escaping to the surface of the liquid, serve to further absorb the internal pressure which would otherwise be exerted to accelerate the liquid. The use of compression chambers to absorb the pressure created in a switch tank upon the separation of the contacts under load is disclosed and claimed in my Patent 1,537,352, May, 12, 1925, which is assigned to the assignee of the present application.

forms than that shown and described, and I, therefore, do not wish to be restricted to the specific construction shown, but intend. to cover by the appended claims all changes and 15 modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is

1'. A fluid break switching apparatus coma tank, means forming -a chamber within said tank, primary contactsseparable within said chamber, secondary contacts separable beneath said chamber within said tank, and cushioning means within said tank adjacent'said secondary contacts, the arrangement being such that pressure produced arc between said secondary contacts is l a rbed by cushioning means. i N 2. Auid break switching apparatus com- 00 prising a tank, means forming a chamber My inuentionmaybe embodied in othern within said tank, primary contacts separable within said chamber, secondary contacts separable beneath said chamber, and cushioning means in contact with the exterior surface of said chamber, the arrangement being such that pressure produced by an arc between said secondary contacts is absorbed by said cushioning means.

' 3. A Huid break switching apparatus comprising a tank, means forming a chamber within said tank, primary contacts separable within said chamber, secondary contacts separable beneath said chamber, and

cushioning means in contact with the inner surface of said tank and the outer surface of said chamber, the arrangement being such that pressure produced by an are between said secondary contacts is absorbed by said cushioning means.

4k. In a iiuid break switching apparatus, a tank containing a liquid, means forming a chamber within said tank, primary contacts separable within said chamber, and secondary contacts separable within said tank beneath said chamber whereby any arc formed upon their separation will vaporize liquid within said tank, Isaid chamber being formed to direct said vapor upwardly along its outer surrace.

5. In a fluid break switching apparatus, a tank containing a liquid, means forming a chamber withinsaid tank, primary contacts separable within said chamber, secondary' contacts separable 'within said tank beneath said chamber whereby any arc formed upon their separation will vaporize liquid within said tank, said chamber .being formed to direct said vapor upwardly along its outer surface, and cushioning means interposed in the path of said vapor, the arrangement being such that pressure produced by an arc between said secondary contacts isabsorbed by said cushioning means.

6. An electric switch of the type wherein a circuit is made and broken within al tank well below the surface of an arc eXtin ishing liquid comprising contacts separa le in a substantially horizontal direction and connected to the switch terminals by means of conducting members, and cushioning means within said tank adjacent said contacts, the

`arrangement being such that any arc formed by the separation of said contacts is blown downwar l by the magnetic field of the switchan pressure' created thereby is absorbed by said cushioning means.

Inl wit-ness whereof, I have hereunto set my hand this 17th day of November, 1922.

JOHN D. HILLIARD. 

